This invention relates to a stitch pattern formation sewing machine for forming arranged combinations of stitch patterns on a fabric by relative movement between a vertically movable needle and a fabric holding means for holding the fabric in accordance with stitch pattern data selected by a select means and arrangement data input by an input means.
When stitch patterns for an insignia or a set of initials are repeatedly sewn with a conventional sewing machine, stitch pattern data stored in a memory means, for example, "a", "b" and "c", are selected on a keyboard and combined and arrangement data is input. The arrangement data comprises direction data for arranging the combination of the stitch patterns in a desired direction and interval data for arranging each of the combinations at appropriate intervals. According to the stitch pattern data and the arrangement data for stitch patterns "a", "b", and "c", a needle is vertically driven and a fabric is moved by a fabric holding means relative to the needle. The combination of the three stitch patterns "a", "b", and "c" is thus formed on the fabric.
In the above conventional sewing machine, when a thread is broken while the stitch pattern "b" is being formed after the stitch pattern "a" has been sewn, the sewing machine is automatically stopped and the fabric is moved back to the beginning point for the stitch pattern "b". Then, the formed portion of the stitch pattern "b" is removed and the needle is threaded. Subsequently, the sewing machine resumes sewing the stitch patterns "b" and "c". When the second combination "abc" is sewn at a specified distance away from the first combination, the position of the fabric relative to the needle is changed by a jog key after the first combination is formed.
Therefore, when a thread breakage happens while multiple combinations of stitch patterns are being sewn, the removal of the stitches of uncompleted stitch patterns is very tedious and time-consuming operation, thus decreasing labor effectiveness.
In addition, in the sewing machine frequent operation of the jog key and a start key is necessary to form the same stitch patterns repeatedly. The tedious operation of the jog key and the start key also decreases the labor effectiveness.